Help with a box for a 12" sundown nightshade d1 in an 02 stratus

I have a 12" sundown nightshade d1 built by woofercooker and am trying to figure out what box would work best in my car. I did a 144.9 with it at the last competition i went to but that was with one of my friends old crx competition boxes that was made for a dd9912 (kurt guenther street b dbdrag champion in 05) lol. Its getting about 2600 watts to it and i like the way it sounds in the box i have which is around 2.48 cubes tuned to 40hz for daily driving. I was just wondering id anyone had any ideas for a box that would work well with the sub and/or my car to see if i could put up some better numbers. Ive heard of people facing the box forwards and sealing off the trunk but am not sure about db gain with it. Any input is appreciated!